1. Field of the Invention
The invention relates to an image processing device, in particular, a technology of enabling a touch panel implemented on the operation panel of the device to respond by vibration to a touch that the touch panel senses.
2. Background
Touch panels have now become established as input devices essential for operation of electric appliances. Indeed, touch panels are included as standard equipment in automated teller machines (ATM) of banks, and in automatic ticket machines of stations. Touch panels are standard input devices of smartphones and tablet terminals, which have become widespread at an explosive pace. In recent years, home electric appliances also include many types with operation panels in which touch panels are implemented.
Such widespread use of touch panels is largely due to a good operational feeling that touch panels provide to users. With touch panels, users can directly touch and operate graphic user interface (GUI) components, such as icons and virtual buttons, displayed on operation screens. The GUI components are hereinafter referred to as “gadgets.” The users have to handle neither keyboards nor mouses. This probably prevents users inexperienced with keyboards and mouses from falling into a situation in which the users are bewildered by operation of gadgets. Such easy-to-grasp operations enable the touch panels to provide users with a good operational feeling.
A known method of improving this operational feeling is, for example, a technology of making a touch panel respond by light or sound to a touch that the touch panel senses. More concretely, the touch panel, when sensing the touch of a user's finger or the like, instructs the display device to change the appearance of gadgets such as their colors, shapes, and brightness, or the speaker to produce electronic sounds. Such visual or auditory response allows the user to perceive “reaction” to the touch on the touch panel, which is also called “click feeling” or “feedback,” thus convincing the user that his/her operation by the touch has been accepted by the device equipped with the touch panel.
As a technique of improving such feedback effect, a touch panel equipped with force-feedback (FFB) function has been developed recently. See for example JP 2006-150865 and JP 2010-282346. The “FFB function” means a function of vibrating a touch panel, in particular its surface, in response to a touch that the touch panel senses. Such vibration, which is hereinafter referred to as “responsive vibration,” enables a user to feel as if the reaction to the user's touch on a virtual button were tactile feedback from a pushed mechanical button. Since the responsive vibration is a tactile response, it can be sufficiently perceived by a user who is kind of bad at sensing change in appearance of gadgets or electronic sounds, such as a child and an elderly person.